Switching device comprising reed contacts operated by permanent magnets



Apnl 14, 1964 G. POSTEL 3,129,302

SWITCHING DEVICE COMPRISING REED CONTACTS OPERATED BY PERMANENT MAGNETS Filed March 29, 1962 r 2 Sheets-Sheet 1 Fig.7

7 INVENTOR q. P05 TEL 71w. My

ATTORNEY 3,129,302 CONTACTS TS April 14, 1964 G. POSTEL SWITCHING DEVICE COMPRISING REED OPERATED BY PERMANENT MAGNE 2 Sheets-Sheet 2 Filed March 29, 1962 INVENTOR qrpas-rcL United States Patent Ofiice 3,129,302 Patented Apr. 14, 1964 3,129,302 SWITCHING DEVICE COMPRISING REED CON- TACTS OPERATED BY PERMANENT MAGNETS Giinter Postel, Madrid-Aravaca, Spain, assignor t International Standard Eiectric Corporation, New York, N .Y., a corporation of Delaware Filed Mar. 29, 1962, Ser. No. 183,632 Claims priority, application Germany Mar. 30, 1961 4 Claims. (Cl. 200-87) The present invention relates to a switching device comprising a plurality of pushbuttons and reed contacts that are operated by permanent magnets, for the use in equipments of telecommunication or other data-processing systems, such as telephone or computing systems. In the switching device according to the invention there are used reed contacts consisting e.g. of two overlapping flat springs arranged inside a protective envelope of glass or any other insulating material and forming the contacting point, or of piston contacts which are moved to and fro inside the protective envelope or glass tube.

It is already well-known to use such reed contacts in key-controlled switching devices. In one conventional type of device of this kind a permanent magnet is mounted in the form of a pushbutton, to a fiat spring arranged vertically in relation to the reed contact. Upon depressing the fiat spring the permanent magnet approches its associated reed contact so that the latter will be operated thereby.

Furthermore there has already been proposed an arrangement comprising a plurality of pushbutton keys in which on the key bodies, which are arranged in the form of a matrix, there are disposed one or more permanent magnets preferably by 90 in relation to one another. Upon actuating one of the keys the associated permanent magnets are displaced in the longitudinal direction and thus operate those of the reed contacts lying closest to the key body. Such an arrangement provides the possibility of transmitting in code form the control signal which is assigned to each one of the keys.

By using reed contacts, such types of key-controlled switching devices have the advantage that they may also be used in systems that are endangered by explosions. In relation to the code signals to be transmitted and, consequently, in relation to the required number of keys these devices call for a large number of reed contacts and associated permanent magnets.

Moreover, there is already known a switching device comprising several keys and reed contacts-that are operated by permanent magnets, in which coordinately arranged coupling elements are provided, at the crossing (intersecting) points of which there are arranged keys carrying permanent magnets and in which, upon actuation of the keys, the one type of coupling elements is moved in the one, and the other type of elements is moved in the direction vertically in relation to the first direction in such a way that on account of this the reed contacts assigned to the coupling elements are operated either individually or in combination. This type of switching device, however, has the disadvantage that the mechanical expenditure necessary for achieving such a switching combination, is a very high one.

It is one object of the present invention to avoid the disadvantages of the conventional types of switching devices. According to the invention this is accomplished in that in recesses or windows of flux-deflecting members of the magnetic circuit there are inserted permanent magnets mounted to pushbutton keys and capable of being moved together therewith by exerting a pressure upon the keys, and that the permanent magnets are so magnetized that the developing magnetic field of a movable permanent magnet will counteract the magnetic field as imprinted upon the flux-deflecting members by the fixed or stationary permanent magnet, so that a previously operated reed contact will be opened, and closed again upon removing the movable permanent magnet.

According to the further embodiment of the invention the permanent magnets may also be magnetized in such a way that the developing magnetic field produced by a movable perment magnet will assist the magnetic field as imprinted upon the flux-deflecting members by the fixed or stationary permanent magnet, so that a previously unoperated reed contact will close, and will be re-opened upon removal of the movable permanent magnet.

According to another embodiment of the invention it is proposed to arrange likewise reed contacts parallel in relation the magnetizing direction of the movable permanent magnets and lying in one plane with the flux-deflecting members, of which each time there are only operated those of the reed contacts which are assigned to a movable permanent magnet, and upon depressing the corresponding key.

According to a still further embodiment of the invention several fixed or stationary permanent magnets each with a magnetic circuit consisting of flux-deflecting members are arranged next to each other and independenltly of one another. Between each time two magnetic circuits that are separated from each other, and in the height of their flux-deflecting members there are arranged further reed contacts capable of being operated by respectively two neighbouring keys. By this arrange ment of the magnetic circuits and of the keys acting thereupon there is achieved a certain coding of the reed contacts to be operated.

The switching device according to the invention ofiiers the advantages of requiring a small number of reed contacts, i.e. a number of reed contacts which is small when compared with the number of code signals to be transmitted and, consequently, when compared with the number of required pushbutton keys, and that all mechanical connecting links or moving parts for controlling or encoding the reed contacts may be omitted with the exception of the actual keys, so that there will result a type of embodiment which is inexpensive in manufacture.

The invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 shows one basic conception of a key or pushbutton field according to the invention in a perspective view, in which the keys have been omitted for reasons of clarity,

FIG. 2 shows two switching devices according to FIG. 1 in a top view, arranged next to each other,

FIG. 3 shows a switching device according to FIG. 1 with a cover plate and the associating pushbutton keys, in a sectional side view, and

FIGS. 4 and 5 each show a permanent magnet one with and one Without pole pieces.

Reference numeral 1 in FIG. 1 indicates a base plate on which are mounted the flux-deflecting members 2 and 3. These flux-deflecting members 2 and 3 are provided at their one ends with inclined portions, and are extended at their other ends by angled-oh bails 4 and 5 between which there is firmly arranged a permanent magnet 6. Near the tapered ends of the flux-deflecting members 2 and 3 there is arranged a reed contact 7 in a glass tube. At a certain spaced relation in the fluxdeflecting members 2 and 3 there are provided recesses or windows (cutouts) 8 into which movable permanent magnets 9 are capable of being inserted by the action of a key pressure. The cover plate and the keys containing the movable permanent magnets 9 are not shown in this drawing in order to provide a better representation of the construction of the magnetic circuit. This magnetic circuit consisting of the permanent magnet 6, the flux-deflecting membersZ and 3 with their angledoif bails 4 and 5 and the reed contact 7 is so designed that by the superposition of magnetic fields there is caused an action upon the reed contact 7. As already mentioned hereinbefore, the flux-deflecting members 2 and 3 which serve to extend the magnetic field of the permanent magnet 6 to the reed contact, are provided with cut-out portions 8 into which the movable permanent magnets 9 are allowed to plunge in order to either weaken or strengthen the magnetic flux in the flux-deflecting members 2 and 3 in dependence upon the magnitude and direction of the magnetization of the movable permanent magnets 9. The magnetic field required for the switching of the reed contact 7 is produced by a permanent or electro-magnet 6 and is extended to the reed contact to be operated, with the aid of the flux-deflecting members. For example, when introducing into a cutout 8 of the flux-deflecting members 2 and 3 a permanent magnet 9 which is polarised in such a way that its magnetic field will counteract the magnetic field as imprinted upon the flux-deflecting members by the firmly arranged (fixed, stationary) permanent magnet 6, in other words: that it weakens the magnetic flux in the flux-deflecting members 2 and 3, then a previously operated reed contact 7 will open, and will be re-closed again upon removal of the movable permanent magnet.

Quite depending on both the direction and intensity of magnetization of the permanent magnets 6 and 9, the switching operation of the reed contact is also reversible. For example, if the magnetic flux in the flux-deflecting members 2 and 3. is so weak that the magnetic circuit is incapable of closing the reed contact 7, then it is possible, by introducing a correspondingly polarized permanent magnet 9 into a cutout 8 of the flux-deflecting members 2 or 3, to increase the magnetic flux within the magnetic circuit to such an extent that the reed contact 7 will be closed reliably, and will be re-opened upon removal of the inserted permanent magnet 9.

For example, if reed contacts 7 are likewise arranged parallel in relation to the direction of magnetization of the movable permanent magnets 9 and in one plane with the flux-deflecting members 2 and 3, then each time only those of the reed contacts are operated (I) which are associated with a movable permanent magnet, upon pressing the respective key. For reasons of providing or enabling a better understanding of the invention, these types of reed contacts are not shown in FIG. 1, but are indicated by the reference numerals 7a, 7b and 7c in FIG. 2.

FIG. 2 shows two magnetic circuits of the type as described in FIG. 1, arranged next to each other on a base plate 1. The reed contact 7 of the one magnetic circuit is denoted by the reference numeral 7' in the second magnetic circuit. As far as the reed contacts 7 or 7' act as back contacts, i.e. in cases where the magnetic field in the magnetic circuit is chosen so strong that the reed contacts 7 and 7' are continuously operated, the reed contacts 7 and 7 are connected in series in the circuit arrangement. In cases where the reed contacts, however, are supposed to act as make contacts, i.e. where the magnetic field in the magnetic circuit is so weak that the reed contacts 7 and 7' are not being closed thereby, the reed contacts 7 and 7' are connected in parallel with respect to the circuit arrangement.

In the following description of the invention there is assumed to exist the first mentioned case, i.e. that the reed contacts 7 and 7' act as back contacts. The cover plate which is not shown in FIG. 2 contains a number of pushbutton keys and movable permanent magnets 9 contained in these keys, corresponding to the number of cutouts (windows, recesses) provided in the flux-deflecting members 2 and 3. For reasons of simplicity the cutouts 8 are indicated by the letters A through I in the arrangement according to FIG. 2. In conformity therewith,

when depressing the key 11 and introducing a permanent magnet 9 into a cutout 8 of the flux-deflecting members 2 and 3, there is simply spoken of the actuation of the key A through I in the following specification.

The reed contacts 7a through 70 are arranged, as already mentioned (FIG. 1), in the first magnetic circuit between the flux-deflecting members 2 and 3. In the second magnetic circuit these reed contacts are designated 7g to 71'. Between the two magnetic circuits further reed contacts 7d to 7 f are arranged in the same way, and are operated by the neighbouring keys of the first or second magnetic circuit respectively.

With the aid of this arrangement it is possible to achieve the following switching functions or encoding forms: For example, if the key A is depressed then the reed contact 7a is closed, and the reed contact 7 is opened; upon pressing the key B there is closed the reed contact 712 and the reed contact 7 is opened; upon pressing the key C there is closed the reed contact 7c and the reed contact 7 is opened; upon pressing the key D there is closed the reed contact 70? and 7a, and the reed contact 7 is opened; upon pressing the key B there closed the reed contacts 7e and 7b, and the reed contact 7 is opened; upon pressing the key F there are closed the reed contacts 7 and 7c, and the reed contact 7 is opened; upon pressing the key G there are closed the reed contacts 7g and 7d, and the reed contact 7' is opened; upon pressing the key H there are closed the reed contacts 7h and 7e, and the reed contact 7' is opened; upon pressing the key E there are closed the reed contacts 7e and 7 and the reed contact 7' is opened; upon pressing the key K there is closed the reed contact 7g and the reed contact 7 is opened; upon pressing the key L there is closed the reed contact 711 and the reed contact 7 is opened; upon pressing the key M there is closed the reed contact 7i and the reed contact 7' is opened. By arranging the magnetic circuits and the keys acting thereupon, in the way as described above, it is possible to achieve a certain code establishment with respect to the reed contacts 7, 7, 7a to 7i that are supposed to be operated.

FIG. 3 shows a switching device according to FIGS. 1 and 2 in a sectional side view. The keys 11 comprising the movable permanent magnets 9 are arranged in a top cover plate 10. The resetting of the key is effected by the action of a restoring spring 12. Between the permanent magnets 9 at normal, when the key is not in the pressed state, and the reed contacts 7, 7, 7a to 71' to be operated, there is arranged a shielding plate 13 provided with corresponding cutouts through which the permanent magnets 9 extend. This screen plate 13 is adapted to bind the stray field of the individual permanent magnets 9 when in their normal position.

FIGS. 4 and 5 show a possibility of better utilizing the permanent magnetic field of the magnet plunging into the flux-deflecting members. This is accomplished by providing the permanent magnets with pole pieces for effecting that the field is extended within the range a-b in the directions as indicated by the arrows (FIG. 5). In this Way it is possible to achieve a certain amplification of the permanent magnetic field at the switching point.

For the use in computers or computing systems this switching device may also consist of more than two magnetic circuits which are arranged next to each other and contain the corresponding number of reed contacts. Instead of using reed contacts with glass or otherwise sealed reeds, it is also possible to use piston contacts.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. A switching device comprising a first pair of spacedapart substantially parallel plates of magnetic material each having a plurality of apertures therein, first flux generating means positioned between said plates near one end thereof to establish a magnetic field in the plates of opposite polarity, first magnetically operable switch means positioned in flux linking relationship with the other end of said plates, a plurality of second magnetically operable switch means positioned adjacent respective ones of said apertures, and a plurality of selectively operable second flux generating means movable into and out of the confines of the associated apertures to vary the said magnetic field thereby operating and restoring the said first switch means and simultaneously movable into and out of flux-linking relationship with the associated second switch means thereby operating and restoring them concurrently with the operation and res toration of the said first switch means.

2. A switching device as set forth in claim 1 wherein the said second flux generating means comprises a permanent magnet.

3. A switching device as set forth in claim 1 wherein certain of the said second flux generating means when operated increase the intensity of said magnetic field linkage to said first switch means and wherein other of said second flux generating means when operated decrease the intensity of the said magnetic field linkage to the said first switch means.

4. A switching device comprising a plurality of magnetic structures positioned adjacent one another and each having a pair of spaced-apart substantially parallel plates of magnetic material with each plate having a plurality of apertures therein, each of said structures having a first flux source positioned between the associated plates near 6 one end thereof and having first switch means positioned in flux linking relationship with the other end thereof, a plurality of second switch means positioned between the plates of each said structure adjacent respective ones of said apertures, a plurality of third switch means positioned between two adjacent switch structures and adjacent apertures in one plate of each of said structures,

a plurality of selectively operable second flux sources movable into and out of the confines of respective apertures to vary the fiux through said plates from said first source to operate and restore the associated said first switch means, the last said movement into and out of the confines of certain of said apertures operating and restoring the associated one of said second switch means concurrently with the operation and restoration of the first switch means, and the last said movement into and out of the confines of certain other of said apertures operating and restoring the associated one of said second switch means and the associated one of the third switch means concurrently with the operation and restoration of the first switch means.

References Cited in the file of this patent UNITED STATES PATENTS 2,814,031 Davis Nov. 19, 1957 2,816,254 Canepa Dec. 10, 1957 2,854,542 Boysen et al Sept. 30, 1958 3,012,116 Boylan et a1. Dec. 5, 1961 OTHER REFERENCES German application 1,082,629, printed June 2, 1960 

1. A SWITCHING DEVICE COMPRISING A FIRST PAIR OF SPACEDAPART SUBSTANTIALLY PARALLEL PLATES OF MAGNETIC MATERIAL EACH HAVING A PLURALITY OF APERTURES THEREIN, FIRST FLUX GENERATING MEANS POSITIONED BETWEEN SAID PLATES NEAR ONE END THEREOF TO ESTABLISH A MAGNETIC FIELD IN THE PLATES OF OPPOSITE POLARITY, FIRST MAGNETICALLY OPERABLE SWITCH MEANS POSITIONED IN FLUX LINKING RELATIONSHIP WITH THE OTHER END OF SAID PLATES, A PLURALITY OF SECOND MAGNETICALLY OPERABLE SWITCH MEANS POSITIONED ADJACENT RESPECTIVE ONES OF SAID APERTURES, AND A PLURALITY OF SELECTIVELY OPERABLE SECOND FLUX GENERATING MEANS MOVABLE INTO AND OUT OF THE CONFINES OF THE ASSOCIATED APERTURES TO VARY THE SAID MAGNETIC FIELD THEREBY OPERATING AND RESTORING THE SAID FIRST SWITCH MEANS AND SIMULTANEOUSLY MOVABLE INTO AND OUT OF FLUX-LINKING RELATIONSHIP WITH THE ASSOCIATED SECOND SWITCH MEANS THEREBY OPERATING AND RESTORING THEM CONCURRENTLY WITH THE OPERATION AND RESTORATION OF THE SAID FIRST SWITCH MEANS. 